Book excerpt: While the basic operating principles of Helical Magnetic Flux Compression Generators are easy to understand, the details of their construction and performance limits have been described only in government reports, many of them classified. Conferences in the field of flux compression are also dominated by contributions from government (US and foreign) laboratories. And the government-sponsored research has usually been concerned with very large generators with explosive charges that require elaborate facilities and safety arrangements. This book emphasizes research into small generators (less than 500 grams of high explosives) and explains in detail the physical fundamentals, construction details, and parameter-variation effects related to them.